X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=709b945094e0e6ae2ba3a488c7b9923bfef3ea23;hb=69e6428ddd3913a53109847328a754d3cb5ce3af;hp=aa51649783f64c0e324c0090c42033cdbbb41f7a;hpb=3a6922c6ab7b4d9455f517ac0bf86dfcede0ef3d;p=lttng-tools.git diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c index aa5164978..709b94509 100644 --- a/src/bin/lttng-sessiond/kernel.c +++ b/src/bin/lttng-sessiond/kernel.c @@ -34,8 +34,16 @@ #include "kern-modules.h" #include "utils.h" +/* + * Key used to reference a channel between the sessiond and the consumer. This + * is only read and updated with the session_list lock held. + */ +static uint64_t next_kernel_channel_key; + /* * Add context on a kernel channel. + * + * Assumes the ownership of ctx. */ int kernel_add_channel_context(struct ltt_kernel_channel *chan, struct ltt_kernel_context *ctx) @@ -63,12 +71,16 @@ int kernel_add_channel_context(struct ltt_kernel_channel *chan, goto error; } } + ret = 0; end: cds_list_add_tail(&ctx->list, &chan->ctx_list); - return 0; - + ctx->in_list = true; + ctx = NULL; error: + if (ctx) { + trace_kernel_destroy_context(ctx); + } return ret; } @@ -163,8 +175,10 @@ int kernel_create_channel(struct ltt_kernel_session *session, cds_list_add(&lkc->list, &session->channel_list.head); session->channel_count++; lkc->session = session; + lkc->key = ++next_kernel_channel_key; - DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd); + DBG("Kernel channel %s created (fd: %d, key: %" PRIu64 ")", + lkc->channel->name, lkc->fd, lkc->key); return 0; @@ -285,7 +299,8 @@ int kernel_disable_channel(struct ltt_kernel_channel *chan) } chan->enabled = 0; - DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd); + DBG("Kernel channel %s disabled (fd: %d, key: %" PRIu64 ")", + chan->channel->name, chan->fd, chan->key); return 0; @@ -309,7 +324,8 @@ int kernel_enable_channel(struct ltt_kernel_channel *chan) } chan->enabled = 1; - DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd); + DBG("Kernel channel %s enabled (fd: %d, key: %" PRIu64 ")", + chan->channel->name, chan->fd, chan->key); return 0; @@ -519,6 +535,7 @@ int kernel_open_metadata(struct ltt_kernel_session *session) } lkm->fd = ret; + lkm->key = ++next_kernel_channel_key; /* Prevent fd duplication after execlp() */ ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC); if (ret < 0) { @@ -644,17 +661,22 @@ error: * Open stream of channel, register it to the kernel tracer and add it * to the stream list of the channel. * + * Note: given that the streams may appear in random order wrt CPU + * number (e.g. cpu hotplug), the index value of the stream number in + * the stream name is not necessarily linked to the CPU number. + * * Return the number of created stream. Else, a negative value. */ int kernel_open_channel_stream(struct ltt_kernel_channel *channel) { - int ret, count = 0; + int ret; struct ltt_kernel_stream *lks; assert(channel); while ((ret = kernctl_create_stream(channel->fd)) >= 0) { - lks = trace_kernel_create_stream(channel->channel->name, count); + lks = trace_kernel_create_stream(channel->channel->name, + channel->stream_count); if (lks == NULL) { ret = close(ret); if (ret) { @@ -673,13 +695,10 @@ int kernel_open_channel_stream(struct ltt_kernel_channel *channel) lks->tracefile_size = channel->channel->attr.tracefile_size; lks->tracefile_count = channel->channel->attr.tracefile_count; - /* Add stream to channe stream list */ + /* Add stream to channel stream list */ cds_list_add(&lks->list, &channel->stream_list.head); channel->stream_count++; - /* Increment counter which represent CPU number. */ - count++; - DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd, lks->state); } @@ -1021,12 +1040,10 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess, /* For each channel, ask the consumer to snapshot it. */ cds_list_for_each_entry(chan, &ksess->channel_list.head, list) { - pthread_mutex_lock(socket->lock); - ret = consumer_snapshot_channel(socket, chan->fd, output, 0, + ret = consumer_snapshot_channel(socket, chan->key, output, 0, ksess->uid, ksess->gid, DEFAULT_KERNEL_TRACE_DIR, wait, nb_packets_per_stream); - pthread_mutex_unlock(socket->lock); if (ret < 0) { ret = LTTNG_ERR_KERN_CONSUMER_FAIL; (void) kernel_consumer_destroy_metadata(socket, @@ -1036,11 +1053,9 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess, } /* Snapshot metadata, */ - pthread_mutex_lock(socket->lock); - ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output, + ret = consumer_snapshot_channel(socket, ksess->metadata->key, output, 1, ksess->uid, ksess->gid, DEFAULT_KERNEL_TRACE_DIR, wait, 0); - pthread_mutex_unlock(socket->lock); if (ret < 0) { ret = LTTNG_ERR_KERN_CONSUMER_FAIL; goto error_consumer; @@ -1086,3 +1101,111 @@ int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits) return kernctl_syscall_mask(chan_fd, syscall_mask, nr_bits); } + +/* + * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi + * version number. + * + * Return 1 on success, 0 when feature is not supported, negative value in case + * of errors. + */ +int kernel_supports_ring_buffer_snapshot_sample_positions(int tracer_fd) +{ + int ret = 0; // Not supported by default + struct lttng_kernel_tracer_abi_version abi; + + ret = kernctl_tracer_abi_version(tracer_fd, &abi); + if (ret < 0) { + ERR("Failed to retrieve lttng-modules ABI version"); + goto error; + } + + /* + * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3 + */ + if (abi.major >= 2 && abi.minor >= 3) { + /* Supported */ + ret = 1; + } else { + /* Not supported */ + ret = 0; + } +error: + return ret; +} + +/* + * Clear a kernel session. + * + * Return LTTNG_OK on success or else an LTTng error code. + */ +enum lttng_error_code kernel_clear_session(struct ltt_session *session) +{ + int ret; + enum lttng_error_code status = LTTNG_OK; + struct consumer_socket *socket; + struct lttng_ht_iter iter; + struct ltt_kernel_session *ksess = session->kernel_session; + + assert(ksess); + assert(ksess->consumer); + + DBG("Clear kernel session %s (session %" PRIu64 ")", + session->name, session->id); + + rcu_read_lock(); + + /* + * Note that this loop will end after one iteration given that there is + * only one kernel consumer. + */ + cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter, + socket, node.node) { + struct ltt_kernel_channel *chan; + + /* For each channel, ask the consumer to clear it. */ + cds_list_for_each_entry(chan, &ksess->channel_list.head, list) { + DBG("Clear kernel channel %" PRIu64 ", session %s", + chan->key, session->name); + ret = consumer_clear_channel(socket, chan->key, + ksess->consumer); + if (ret < 0) { + goto error; + } + } + + if (!ksess->metadata) { + /* + * Nothing to do for the metadata. + * This is a snpashot session. + * The metadata is genererated on the fly. + */ + continue; + } + + /* + * Clear the metadata channel. + * Metadata channel is not cleared per se but we still need to + * perform rotation operation on it behind the scene. + */ + ret = consumer_clear_channel(socket, ksess->metadata->key, + ksess->consumer); + if (ret < 0) { + goto error; + } + } + + goto end; +error: + switch (-ret) { + case LTTCOMM_CONSUMERD_RELAYD_DISALLOW_CLEAR: + status = LTTNG_ERR_CLEAR_RELAY_DISALLOW; + break; + default: + status = LTTNG_ERR_CLEAR_FAIL_CONSUMER; + break; + } +end: + rcu_read_unlock(); + return status; +}